Ore concentration



' radical R. selected.

v compounds of the type Patented Aug. 13, 1935 UNITED STATES PATENT OFFICE oar. CONCENTRATION of Maryland No Drawing. Application March 1, 1930, Serial No. 432,563

8 Claims. (01. 209 10s) This invention relates to ore concentration with compounds of organic substituted monothio-carbonic acid, and is herein illustrated in froth-flotation procedures carried out with compounds containing the hydrocarbon radicals which form alcohols, such as the ethyl or benzyl alcohols. Such compounds are unsaponiflable BO-fi-SM wherein R is a hydrocarbon radical and M is hydrogen or a metal or another A number of these compounds are easily prepared in a form pure enough for ore concentration, when carbon-oxy-sulphide is passed into a solution of a caustic alkali, such as an alkali metal hydroxide, for example, potassium hydroxide, in the alcohol. containing the hydrocarbon These compounds are relatively cheap substances, and as illustrated below, are effective on a variety of ores when used in small amounts. It is found, for example, that iron-bearing copper ores can be concentrated by the aid of these derivatives so as to yield concentrates rich in copper and yet reject a large proportion of the undesired iron.

It may be noted that carbon-oxy-sulphide' is readily and cheaply made by conducting carbon monoxide and sulphur vapor through hot clay or porcelain tubes, or subjecting such a mixture to electrical discharges. For testing purposes it has been prepared by the action of sulphuric acid on potassium sulphocyanide', being purified by passing through strong caustic soda solution and sulphuric acid.

Example I .Utah copper ore was reground wet to pass 80-mesh with lime, equal to four, pounds of calcium oxide per ton of dry ore, and made into a pulp with more water in a minerals separation subaeration testing machine and agitated for two minutes with 0.25 pound of potassium ethyl mono-thio-carbonate and 0.1 pound of pine oil, both per ton of ore. Froth was then removed for five minutes during continued agitation, yielding a copper concentrate. The results are shown in the following'table: 1

Somewhat inferior but useful results were obtained when the pulp was neutral or acid.

Example II.-Another lot of the same ore was similarly ground with lime and similarly agitated with 0.25 pound of potassium amyl mono-thiccarbonate and 0.1 pound of pine oil, both per ton of ore. removed for five minutes during continued agi- After two minutes agitation, froth was Somewhat inferior but useful results were obtained when the pulp was neutral or acid.

Example III.Another lot of the same ore was similarly ground with lime and similarly agitated with 0.1 pound of potassium ethyl mono-thiacarbonate and 0.2 pound of cresylic acid, both per ton of ore. After two minutes agitation a rougher froth concentrate was removed for five minutes during agitation. This rougher concentrate was put back into the machine with the further addition of 0.05 pound of the-cresylic acid per ton of the ore, and reagitated for two minutes, and then a cleaned froth concentrate removed during three minutes agitation. The tails from this operation constituted a middling. The

The large rejection of iron will be noted,

Example IV.-Another lot of the same ore was similarly ground with lime and similarly agitated with 0.1 pound of potassium amyl mono-thiccarbonate and 0.2 pound of cresylic acid, both per ton of ore, agitated for two minutes, and a rougher froth concentrate removed during continued agitation for five minutes. The rougher concentrate was put back into the machine and reagitated and a cleaned froth concentrate removed for three minutes. The tails from this operation constituted a middling. The results are shown in the following table:

Assays Recoveries Per cent wt.

Percent Percent Inso] Percent Percent Cu Fe u Fe Heads 100.0 1.048 2.96 100.00 1(1100 30. 8 9 4 81. ll 44. 71 7. 6 7.44 8.48 l. ll. 45 46. 81

Example V. Phelps-Dodge ore was reground I wet to pass 85-mesh with lime equal to two pounds of calcium oxide per ton of dry ore, and made into a, pulp with more water in a similar machine and agitated for two minutes with 0.15 pound of potassium ethyl mono-thio-carbonate,

- and 0.15 pound of dark cresylic acid (95-l00% pure), and a rougher froth concentrate separated for ten minutes. This concentrate was reground v for five minutes with one pound of calcium oxide per ton of the ore, and then reagitated with the further addition of 0.05 pound of the cresylic acid per ton of the ore, and separated into a finished concentrate and a middling. The results are shown in the following table:

Assays Recoveries Per cent wt. I

Percent Percent Insol Percent Percent Fe Cu F Results obtained with the butyl and benzyl, and with the cyclohexyl, compounds of mono-thiccarbonic acid were almost as useful as those obtained withthe ethyl and amyl compounds.

The lead and copper salts of ethyl mono-thiocarbonic acid were also useful, especially in pulps pound of pine oil, both per ton of ore, and then a froth concentrate was separated for five minutes. The results are shown in the following table:

I Assay par 4 Per cent Per cent wt 5 cent Pb recovery Pb 4. 75 100. (I) 51. 2 Q8. 08 0. l 1.92

Example VII.Ten-mesh ore from Universal Exploration Company was reground wet with two pounds of calcium oxide and one and one-half pounds of copper sulphate, both per ton of ore, until only 2% of the ore was coaiserthan 48- mesh and 48% passed ZOO-mesh. The ore was then made into a pulp with more water and agitated for five minutes with 0.3 pound of potassium ethyl mono-thio-carbonate, 0.4 pound of Barrett No. 4, and 0.15 pound of pine oil, all per ton of ore, and a rougher froth concentrate separated for five minutes. This concentrate was then put back in the machine and reagitated with further addition of 0.05 pound of potassium ethyl mono-thio-carbonate per ton of original ore, agitated for two minutes, and thus was separated into a finished concentrate and a middling. The results are shown in the following table:

Example VIII.-Ten-mesh ore of the Leadville Lead-Zinc Company was reground with 6 pounds of sodium carbonate, 02 pound of sodium cyanide, and 2 pounds of zinc sulphate, all per ton of ore, until 94% passed 200-mesh. The ore was made into a pulp with more water and agitated for five minutes while separating a froth, with thefurther addition of 4 pounds of sodium carbonate, 0.1 pound of potassium ethyl mono-thiccarbonate and 0.15 pound of dark cresylic acid (95 to 100 per cent) all per ton of ore. This yielded a rougher lead concentrate, and a tailing to he treated for the recovery of the zinc. The rougher lead concentrate was put back in the machine and reagitated for ten minutes while separating a finished lead froth concentrate, there having been added 0.2 pound of potassium ethyl mono-thio-carbonate, 0.1 pound of the'cresylic acid, 0.1 pound of pine oil and 0.1 pound of Barrett No. 4, all per ton of original ore. The tailing from this operation constituted a lead middling. The first tailing was agitated for ten minutes while a zinc rougher froth was separated, there having been added 5 pounds of calcium oxide, 2.5 pounds copper sulphate, 0.2 pound of potassium ethyl mono-thio-carbonate, 0.3 pound of Barrett No. 634, and 0.05 pound of pine oil, all per ton of original ore. The tailings from this operation constituted the final tailings. This rougher zinc concentrate was put back into the machine and reagitated and separated into a finished zinc concentrate and a zinc middling. The results are shown in the following table:

Example IX.Ten-mesh Parroquia ore from Zacatecas, Mexico, was reground in a laboratory ball mill with water with 6 pounds sodium carbonate, 0.2 pound sodium cyanide, and 3 pounds of zinc sulphate, all per ton of ore, until 91.5% passed 200 mesh. The ore was made into a pulp with water and agitated for 7 minutes during the separation of a. rougher copper-bearing froth, there having been added 0.15 pound per ton of potassium ethyl mono-thiocarbonate and 0.2 pound of the cresylic acid, both per ton of ore. Thetailings'from this operation were later used for the recovery of zinc. This rougher froth concentrate was put back into the machine and reagitated for three minutes during froth separation, there having been added 1 pound of zinc sulphate and 0.1 pound of the cresylic acid, both per ton of ore, and separated into a finished copper concentrate and a copper middling. The first tailing was then put back into the machine with the further addition of one pound of copper sulphate, 0.15 pound potassium ethyl-mono-thiocarbonate and 0.3 pound of Barrett No. 634, all per ton of ore, and agitated with froth separation for seven minutes to yield a rougher zinc froth concentrate. The tailings from this operation constituted the flnartailings. The rougher zinc frothconcentrate was then put back into the machine and agitated for five minutes with the separation of a finished zinc froth concentrate, there having been added 0.1 pound of potassium ethyl-mono-thio-carbonate, 0.05 pound Barrett No. 634, and 0.05 pound pine oil, all per ton of ore. The tailings from this operation constituted a zinc middling. The results are shown in the following table:

Example X.Ten-mesh ore from Mazapil Copper Company, representing material from No. 2

waste dump and largely oxidized, was reground wet until 90% passed 200-mesh. The ground material was made into a pulp with water and agitated for five minutes with 0.1 pound of potassium ethyl-mono-thio-carbonate and a first froth concentrate separated. The remaining pulp was then further agitated for five minutes with 2 pounds sodium sulphide, 2 pounds potassium ethyl mono-thio-carbonate, 0.25 pound Barrett No. 4, and 0.1 pound pine oil, all per ton of ore. A froth concentrate was then separated for five minutes, and a large part of the oxidized copper mineral was recovered in the concentrate. The results are shown in the following table:

Example XI .-Teri-mesh Colossus Mining Company ore was reground wet until 74% passed 200 mesh. The ground ore was made into a pulp with water and agitated with 0.3 pound of potassium ethyl mono-thio-carbonate, 0.6 pound of Barrett No. 4, 0.15 pound pine 011, all per ton of ore, and a rougher froth concentrate separated f or seven minutes during the agitation. The concentrate thus obtained was put back in the machine and reagitated with 0.05 pound of the potassium ethyl mono-thio-carbonate and 0.05 pound of pine oil, both per ton of original ore, and a finished froth concentrate separated, the tailings from this operation constituting a middling. The recovery of values was about the same as in the best results hitherto obtained, and the ratio of concentration was superior toany obtained with concomitant large recoveries. The results are shown in the following table:

In addition to the salts of ethyl mono-thiccarbonic acid other compounds may be used such as the disulphide obtained when potassium ethyl mono-thio-carbonate is treated with ferricyanide of potassium, such disulphide being variously designated as ethyl-carbonic acid disulphide'and dicarbethoxy disulphide.

Example XII .-Utah Copper Company ore was wet ground for ten minutes so that the ore passed 80-mesh and was then made into a pulp with water and agitated with 0.1 pound of pine oil and 0.25 pound of the disulphide describe above, both per ton of ore, to yield a froth concentrate of 11.60% copper and tailings of 0.28% copper, representing a recovery of 75.5% of thecopper.

Example XIII .Another similar lot of the same ore similarly ground was made into a pulp and agitated with the pine oil and the disulphide aforesaid and with the further addition of '7 pounds of sulphuric acid per ton of ore, to yield a froth concentrate. This lotof ore contained 1.058% copper, the concentrate 11.28% copper,

" and the tailings 0.12% copper, representing a recovery of 89.6% of the copper.

Example XIV.Another similar lot of the same ore was ground similarly but with the addition of lime equal to 4 pounds per ton of the ore, and then made into a pulp and agitated with the pine oil and the disulphide aforesaid, to yield a froth concentrate. This lot of the ore contained 0.966% of copper, the concentrate 12.56% copper, and the tailings 0.13% copper, representing a recovery of 87.47% of the copper.

Having thus described certain embodiments of the invention, what is claimed is:

1. The process of concentrating an ore carrying gangue and a value which consists in agitating and aerating a pulp of the ore with a mineralfrothing agent and a compound of the type in an amount of less than half a pound per ton of the ore, wherein R is a hydrocarbon radical and M is a hydrogen or a metal or another so as to obtain a floating concentrate substantially dependent upon the presence of the com pound for an enhanced proportion of value and diminished proportion of gangue in the concentrate compared with a concentrate obtained in the absence of the compound.

2. The process. of concentrating an ore carrying gangue and a value which consists in agitating and aerating a pulp of the ore with a mineralfrothing agent and a compound containing an alkyl substituted mono-thio-carbonic acid radical in an amount of less than half a pound per ton of the ore so as to obtain a floating concentrate substantially dependent upon the presence of the compound for an enhanced proportion of value and diminished proportion of gangue in the concentrate compared with a concentrate obtained in the absence of the compound.

3. The process concentrating an ore carrying gangue and a vaiue which consists in agitating and aerating a pulp of the ore with a mineralfrothing agent and with a salt of an alkyl substituted mono-thio-carbonic acid in an amount of less than half a pound per ton of the ore so as to obtain a floating concentrate substantially dependent upon the presence of the salt for an enhanced proportion of value and diminished proportion of gangue in the concentrate compared with a concentrate obtained in the absence of the salt.

4. The process of concentrating an ore carrying gangue and a value which consists in agitating and aerating a pulp of the ore with a mineral-frothing agent and an ethyl mono-thiocarbonate in an amount of less than half a pound per ton of the ore so as to obtain a floating concentrate substantially dependent upon the presence of the carbonate for an enhanced proportion of value and diminished proportion of gangue in the concentrate compared with a concentrate obtained in the absence of the carbonate.

5. The process of concentrating an ore carrying gangue and a value which consists in agitating and aerating a pulp of the ore with a mineral frothing agent and a salt of ethyl-mono-thiocarbonic acid in an amount of less than half a pound per ton of the ore so as to obtain a floating concentrate substantially dependent upon the presence of the salt for an enhanced proportion of value and a diminished proportion of gangue in the concentrate compared with a concentrate obtained in the absence of the salt.

6. The process of concentrating an ore carrying gangue and a value which consists in agitating and aerating a pulp of the ore with a mineralfrothing agent and an alkali salt of ethyl monothio-carbonic acid in an amount of less than half a pound per ton of the ore so as to obtain a floating concentrate substantially dependent upon the presence of the salt for an enhanced propor tion of value and a diminished proportion of gangue in the concentrate compared with a con-' tion of gangue and of iron in the concentrate I compared with a concentrate obtained in the absence of the salt. I

8. The process of concentrating a copper ore carrying gangue and a normally floatable iron mineral which consists in grinding the ore with lime, agitating and aerating a pulp of the ground ore with a mineral-frothing agent and a salt of ethyl substituted mono-thio-carbonic acid so as to obtain a floating concentrate substantially dependent upon the presence of the salt for an enhanced proportion of copper and a diminished proportion of gangue and of iron in the concentrate compared with a concentrate obtained in the absence of the salt.

CORNELIUS H. KELLER. 

